Hi countrymamma35.
I've had two mammograms. They really aren't that bad. First they put several of these sticky dots with metal beads on each breast (which had me cracking up, because they are cold!). Then the breast is placed on the lower plate of the xray machine. The upper plate is lowered on top, forming that 'breast sandwich'.

I felt a little pinch for a second and pressure, a little uncomfortable, but it didn't really hurt. Xray is taken and then the breast is released. They adjust the xray machine and re-postion you and take the next xray, and so on. Each xray probably takes less than a minute. Compare it to when you go to the dentist and get xrays. Between positioning the film in your mouth and taking the xray, there's only seconds. The whole procedure takes about 10-15 minutes depending on how many xrays are taken, and that's only because you have to wait around for the technician to check the xrays and make sure they came out clear. Every woman is different, this is how it was for me. My description probably sounds worst than the actual procedure but a good xray technician will talk you thorough it and try to make you feel comfortable, so don't be scared. You really shouldn't cancel anymore appointments. Go and get that mammogram done.
PS-You can also check out MRI as an alternative. Not sure how they compare, but something else to think about.